Fuel cells may power laptop computers

New-generation fuel cells may soon replace rechargeable batteries in laptop computers, following work carried out by Cambridge-based company CMR Fuel Cells of Britain.

This development means that users would not need to switch off their laptop and find somewhere to plug it into a power supply to recharge the battery; they will be able to carry on working.

The power is provided by a small cartridge of methanol fuel. When it runs out, the user can slot another one into the onboard fuel cell unit - just like putting a refill in a pen.

CMR engineers are working on prototypes that claim to be smaller, lighter, cheaper and more efficient than conventional fuel cells or lithium-ion batteries.

The company is also part of a working group formed by Intel that is specifying this next generation of portable power sources and it expects the technology to become available in mass-market products from 2010.

Michael Priestnall, now CMR's chief technology officer, came up with the idea for a better, small fuel cell after explaining to his colleague Mike Evans, at Cambridge consultancy Sagentia, why fuel cells had to be so bulky.

"It wasn't so much a eureka moment as a eureka week or two," said Priestnall.

"Over a coffee, I'd been answering Mike's question about the differences between car engines and fuel cells, and why the fuel cell principle depended on keeping the fuel intake totally separate from the oxidant intake."

"It occurred to me that if you could find an alternative to the normal catalyst - platinum, which is used on both sides of a fuel cell - you could select a specific catalyst for each of the anode and cathode of the fuel cell, and that would mean you would no longer need to keep the fuel and air separate."

Although laptop computers will be the first mass-market application for CMR's compact fuel cells, many other potential customers are also interested in low-cost fuel cells that can operate on high-energy fuels.

"The core concepts that CMR have patented can apply to any fuel cell. If CMR don't want to enter other markets at this stage, they have the potential to generate good revenue streams from licensing their technology to other manufacturers who may be targeting applications such as mobile phones, standby power units or even automotive - electric scooters, for example," said Martin Lipscombe, patent attorney at Nash Matthews.

Fuel cells have been around since British scientist William Grove published the first paper describing a hydrogen-oxygen platinum fuel cell in 1839, although it took until the 1960s for them to become a practical proposition.

Similar to batteries, they deliver a constant electrical current but differ from batteries in that they produce electricity from external supplies of fuel (on the anode side) and oxidant (on the cathode side). These react electrochemically in the presence of a catalyst.

The reactants flow in and reaction products flow out, while the chemical energy is converted directly and very efficiently to electricity. Fuel cells can operate virtually continuously as long as the necessary flows are maintained. Their big advantages are high efficiency, silent operation and low emissions.

Until now, the main challenges for fuel cells have been their high cost and low performance.